Reactions of silver iodide with N2O4 and with its dissociation products at 320-550 K

One method of removing radioactive iodine from gaseous media is absorption by a heterogeneous reaction with silver nitrate. Thermodynamic calculations show that when iodine is removed from a coolant based on N2O4 at temperatures of 300-500 K the equilibrium of the reaction is shifted strongly toward the original components, but increase of temperature favors the forward reaction. In this paper the authors report the results of an experimental study of the reactions of silver iodide with N2O4 and with the products of its reversible dissociation in the temperature range 320-580 K under 0.1 MPa pressure. In media with high nitrogen dioxide concentrations silver iodide was found to undergo chemical changes with formation of silver nitrate. The rate of conversion of silver iodide and the kinetic parameters of the process are different if the silver iodide is deposited on silica gel. The existence of a temperature region with negative temperature coefficients of reactions in the systems AgI-N2O4 (T > 390 +/- 10 K) and AgI (SiO2-N2O4) (T > 450 +/- 10 K) was established